✨ Added support for immediate offloaded jobs

closes #117

- Having immediately executable offloaded jobs is necessary to be able to run usecases like: send batched emails now, or any other job that does not need to be scheduled
- Changed "simple" job timeout to make tests run faster

ghost/job-manager/lib/assemble-bree-job.js

@@ -19,11 +19,11 @@ const assemble = (when, job, data, name) => {
         Object.assign(breeJob, {
             date: when
         });
-    } else if (isCronExpression(when)) {
+    } else if (when && isCronExpression(when)) {
         Object.assign(breeJob, {
             cron: when
         });
-    } else {
+    } else if (when !== undefined) {
         Object.assign(breeJob, {
             interval: when
         });

ghost/job-manager/lib/job-manager.js

@@ -90,7 +90,7 @@ class JobManager {
             }
         }
 
-        if (!(at instanceof Date)) {
+        if (at && !(at instanceof Date)) {
             if (isCronExpression(at)) {
                 schedule = later.parse.cron(at, true);
             } else {
@@ -102,8 +102,10 @@ class JobManager {
             }
 
             this.logging.info(`Scheduling job ${name} at ${at}. Next run on: ${later.schedule(schedule).next()}`);
-        } else {
+        } else if (at !== undefined) {
             this.logging.info(`Scheduling job ${name} at ${at}`);
+        } else {
+            this.logging.info(`Scheduling job ${name} to run immediately`);
         }
 
         const breeJob = assembleBreeJob(at, job, data, name);

ghost/job-manager/test/job-manager.test.js

@@ -113,6 +113,70 @@ describe('Job Manager', function () {
 
             clock.uninstall();
         });
+
+        it('schedules a job to run immediately', async function () {
+            const jobManager = new JobManager(logging);
+            const clock = FakeTimers.install({now: Date.now()});
+
+            const jobPath = path.resolve(__dirname, './jobs/simple.js');
+            jobManager.scheduleJob(undefined, jobPath, undefined, 'job-now');
+
+            should(jobManager.bree.timeouts['job-now']).type('object');
+
+            // allow scheduler to pick up the job
+            clock.tick(1);
+
+            should(jobManager.bree.workers['job-now']).type('object');
+
+            const promise = new Promise((resolve, reject) => {
+                jobManager.bree.workers['job-now'].on('error', reject);
+                jobManager.bree.workers['job-now'].on('exit', (code) => {
+                    should(code).equal(0);
+                    resolve();
+                });
+            });
+
+            await promise;
+
+            should(jobManager.bree.workers['job-now']).type('undefined');
+
+            clock.uninstall();
+        });
+
+        it('fails to schedule a job with the same name to run immediately one after another', async function () {
+            const jobManager = new JobManager(logging);
+            const clock = FakeTimers.install({now: Date.now()});
+
+            const jobPath = path.resolve(__dirname, './jobs/simple.js');
+            jobManager.scheduleJob(undefined, jobPath, undefined, 'job-now');
+
+            should(jobManager.bree.timeouts['job-now']).type('object');
+
+            // allow scheduler to pick up the job
+            clock.tick(1);
+
+            should(jobManager.bree.workers['job-now']).type('object');
+
+            const promise = new Promise((resolve, reject) => {
+                jobManager.bree.workers['job-now'].on('error', reject);
+                jobManager.bree.workers['job-now'].on('exit', (code) => {
+                    should(code).equal(0);
+                    resolve();
+                });
+            });
+
+            await promise;
+
+            should(jobManager.bree.workers['job-now']).type('undefined');
+
+            // note: job name resolves to [Object object], test can be made more precise
+            //       once that is fixed in Bree.
+            (() => {
+                jobManager.scheduleJob(undefined, jobPath, undefined, 'job-now');
+            }).should.throw('Job #1 has a duplicate job name of [object Object]');
+
+            clock.uninstall();
+        });
     });
 
     describe('Remove a Job', function () {

ghost/job-manager/test/jobs/simple.js

@@ -1 +1 @@
-setInterval(() => process.exit(0), 100);
+setInterval(() => process.exit(0), 10);